So what would the basic concepts be for this game?
- Diverse crew: Okay, the original movies had a bunch of humans and Spock (with other non-humans among the nameless crew), but The Next Generation has a Klingon, a half-Betazoid (granted, she looks human) and an android among the main characters. In a group of five characters, I'd probably rule that there can be no more than two of any given race.
- Worldbuilding: Races aren't from one planet with all the PHB races living in harmony. Each "planet" (actually some sphere in the Astral Sea) has at most two races (with some interesting relationship). Each player gets to detail the planet they're from. The "Federation" of known worlds then consists of the homeworlds of the player characters, with everything else a possible surprise.
- No material plane: The Normal World, Feywild and Shadowfell aren't their own thing separate from the Astral Sea and the Elemental Chaos. They're just planets among others, floating in the Astral Sea. Actually, the Elemental Chaos might be toned down a bit too.
- Planet of Hats: As with player races, monsters live in monocultures. There's a hobgoblin planet to land on and get in trouble, for example. Next week, the crew finds a sahuagin planet...
- Spelljammers ahoy: The high-tech of Trek becomes magitech. Spelljammers instead of spaceships, and everything else works mostly as usual in D&D.
- Overly obvious moralizing: Er... I'd skip that part.